The environmentally safe and economical production of clean drinking water continues to be a source of concern throughout the world. Typically, where the primary source of drinking water lies just under the ground surface, wells are used to obtain the water. Typical wellfields, whether involving single or multiple wells, are highly susceptible to bacterial invasion during use. Bacteria causes biofouling of the well screen and/or the well formation, decreasing well efficiencies and creating treatment problems for the water obtained. Therefore, the periodic rehabilitation of wells is required to prevent bacterial contamination.
Further, increasingly more stringent Safe Drinking Water Act regulations will require higher levels of treatment for raw water. Also, high bacteria levels in groundwater and raw water pipelines create problems with the more advanced treatment methods.
Conventional means of groundwater bacteria control using gross quantities of chlorine and acid based chemicals may be damaging to the wells in the long-term. Further, conventional means may also jeopardize advanced treatment methods, for example methods utilizing membranes. Additionally, bacteria control chemicals are typically transported and stored on site in a liquid state. Such liquid state chemicals pose an increased the risk to the environment.
In many areas chlorine combined with naturally occurring organics in the groundwater create carcinogenic by-products such as trihalomethanes, which poses a human health risk. Trihalomethanes are created when organics in the well are mixed with large amounts of sodium hypochlorite.
The use of calcium hypochlorite alone may cause plugging of the well.
It is therefore an object of the invention to overcome the foregoing water treatment problems. It is further an object of the invention to:
Reduce chemical usage and decrease environmental and health risks;
Increase well efficiency and reduce operational costs;
Decrease conventional well rehabilitation costs;
Support advanced treatment technologies in meeting more stringent drinking water regulations;
Provide a unit with easy installation and minimal maintenance; and
Provide affordable bacteriologically controlled drinking water to all size water users.